Printing mechanism.



G. E. PANGOAST.

. PRINTING MECHANISM. APPLICATION EILED NOV.8, 1902. RENEWED DBO. 3, 1904.

. 1 4 72 Patented Aug. 11, 1914.

Wl WITNESSES: INVENTOR ATTORNEYS I ATENT and GEORGE E. PANCOAST, 0F BROOKLYN, NEW YORK, ASSIGNOR TO AMERICAN LITHU- GRAPHIC COMPANY, A CORPORATION OF NEW YORK.

PRINTING MECHANISM.

mo em.

Application filed November 8, 1902, Serial No. 130,499

Specification of Letters Patent.

T 0 all whom it may concern:

Be it known that I, GEORGE E. PANOOAST, a citizen of the United States, resident of the borouglr of Brooklyn, county of Kings, State of New York, have invented new and useful Improvements in Printing Mechanism, of which the following is a specification.

My invention relates to printing mechanism and especially to mechanism for back printing orperfecting paper which has been printed in colors on one side.

In applying the rotary press principle to the better grades of printing great difliculty has been experienced in preventing the oil'- set which takes place in the second or perfecting printing mechanism. The offset is due to the fact that part of the ink applied to the paper by the first printing couple is deposited on the impression surface 'of the second printing couple, which surface aftera few impressions becomes so charged with ink as to cause a smut or offset on the surface of the paper which comes in contact therewith. Many-devices have been used to prevent this charging of the impression surface of the second printing couple with the ink of a previous impression. A common way of effecting this purpose consists in leading a Web of paper between the second impression surface and the paper being printed. This method is objectionable, however, because the offset web removes a part of the ink of the first impression on the paper being printed and thus very materially reduces the gloss or brilliancy of that impression. This defect is very marked in multicolor work and especially in multicolor lithographic work. This method'is expensive, moreover, because the web has to be frequently renewechand a more or less complicated mechanism is required to handle the web. lVhen applied to web presses, this mechanism requires considerable space in the machine and on this account'also it is objectionable and not capable of universal application.

My invention has for an object to provide a perfecting printing mechanism, the impression surface of which is of such a nature that it will not receive a deposit of ink from the previous impression or impressions on the paper; also to provide a mechanism of the character referred to, which is simple in construction and operation, and in which construction, also, the

the ink-repelling characteristic of the impression surface may be perfectly developed and permanently maintained. These and other objects of my invention will more fully appear from the following description.

My invention consists in the novel parts, improvements and combinations herein shown and described.

The accompanying drawing, which is referred to herein and forms a part hereof, illustrates one embodiment of my invention and serves in connection with the description herein to explain the principles thereof and the best mode contemplated by me of carrying these principles into effect.

The drawing consists of a diagrammatic view illustrating a multicolor printing press with a perfecting printing couple constructed in accordance with my present invention associatedtherewith, the cylinders of the perfecting couple being shown in section.

Referring to the drawing in detail, 1 represents the frame of the machine, 2 a large central impression drum, and 3 a series of design cylinders arranged circumferentially around the drum and adapted to be brought into printing contact therewith. Each design cylinder is provided with an inking mechanism 4. and preferably also with a damping mechanism 5. A Web of paper 6 is led from a supply roll 7 around the impression drum 2, where it receives on one of its surfaces a series of impressions from the design cylinders 3.

In accordance with the construction shown in the figure, the web after having passed under all of the design cylinders 3 is led away from the impression drum 2 over a suitable guide roller 8 and is passed through the perfecting printing mechanism shown at thebottom of the figure.

In accordance with my invention this perfecting printing mechanism comprises a printing member having a yielding design surface and an impression member having a rigid ink-repelling impression surface. Preferably the ink-repelling characteristic of the impression surface is produced by .moisture, means being provided in the machipe to keep the impression surface in a molst condition. According to the-preferred yielding design surface is in the formofa' transfer or second-, ary deslgn surface which receives its design from a su table rigid primary designsurface.

The perfecting printing mechanism shown consists of a primary design cylinder 9, a secondary printing cylinder 10, and an impression cylinder 11. Primary cylinder 9 is provided with a suitable inking mechanism 12 and, where it is planographic in character, with a suitable damping mechanism 13 also.

The impression cylinder 11 is preferably provided with a surface which may be developed and made ink-repelling upon'the principle of the non-printing port-ions of a lithographic design surface, that is to say, it is made of such a material or is given such a surface character or texture or porosity that when the gummed and etched in sub stantially the same way that lithographic design surfaces are gummed and etched it will, at every part of its surface, when moistened, refuse to take or hold any ink or other greasy substance. It is to be noted in this connection that no surface, which maintains a film of moisture merely mechanically, even though the surface is porous and is treated with an acid to remove all traces of grease and thoroughly clean it, will b permanently ink-repelling. It is essential that .the surface be so treated that it will not absorb ink even if ink is applied when the surface is dry. Something more than a mere mechanical separation of the ink from the impression surface by a film of water is required. The

surfac must be incapable when moistened of retaining any grease that may have been applied to the surface when it was dry.

In accordance with my invention the surface is preferably made of zinc or aluminum, but other porous metallic surfaces may be used, or the surface may consist of lithographic stone, or other suitable calcarious substance. The required permanent ink-repell'ing quality of the surface is obtained by treating the same with a solution of gum arabic to which a small quantity of a suitable acid has been added. The acid should be such as will not materially corrode the surface, the purpose of the acid being not so much to bite or etch the surface as to set or harden the gum. Where zinc or a similar metallographic metal is used, phosphoric acid is suitable Nitric acid is preferable where a calcarious substance is used. I uch an ink-repelling surface, however, is sensi- ,tivel and short-lived as compared with the ordinary impression surface, and if it 'were made flexible or yielding, as impression surfaces have been heretofore universally made in ractice, it would soonbe destroyed or ren 'ered ineffective by the continual bending or flexing caused by the rolling contact -:--,with the design surface under. the heavy pressure required in printing. To avoid these d fficult es, the impression surface in accordance with my invention is, when in constituted and I given a suitable place, substantially rigid and inflexible and the design surface is made somewhat yield-- ing or flexible, so that it will cooperate with the impression surface and' roduceperfect impressions without subjecting the impression surface to a destructive pressure or wear. When the impression surface is to be used in a rotary press it is formed or mounted on a cylinder, and in order that it may be readily removed from the press and another substituted in its place at intervals,

as is required on account of its short life, the impression member is. preferably made thin and light and is removably secured to a rigid supporting cylinder 14.

A suitable damping mechanism is provided for continuously applying moisture to the surface of the impression member 11. As indicated in the drawing this damping mechanism may consist of a pair of applying .rollers 15, a distributing roller 16, a ductor 17, and a fountain roller 34: mounted in the fountain 18.

The design member 10 which cooperates with the impression member 11 may be provided with any form of design surface which is substantially flexible or yielding in its nature. Preferably the surface of the design member 10 is formed of a suitable rubber composition which may consist of a inner layer 19 of hard rubber and an outer thin layer 20 of softer rubber, the whole being vulcanized in place upon the. outer surface of the inner supporting cylinder 21, and then turned and ground or otherwise shape and surface finished. The primary design cylinder 9 may be of any. suitable construction and may be provided with any desired form of design surface, relief or lithographic,

Any suitable means (not shown) may be provided for separating the cylinders 9, 10 and 11 and for bringing them together again with the necessarypressure', and for moving the inking and damping mechanisminto and.

out of contact with the-cylinders 9 and 11,. as is required in stopping and starting the printing operation of the press.

It is among the advantages of my invention that the cumbersome and troublesome offset web may be dispensed with in the perfecting printing mechanism; that none of the ink of the first impression or impressions 'is removed by the perfecting operation; that the perfecting mechanism with its accessories occupies but little more space in the press than an ordinary non-perfecting printing couple and therefore may be so located in the machine that the web passes directly to it from the multi-color-printing mechanism,

and that the construction is simple anddurable and reliable in operation and may be cheaply maintained. When the preferred forms of design and impression members are used,.1ittle or no'preparation or make ready is required to put the press in condition for the printing operation.

My invention in its broader aspects is not limited to the precise construction shown and described, nor to the precise constrution by which it may be carried into effect, as many changes may be made therein without departing from the main principles of the invention and without sacrificing its main advantages.

What I claim as new, and desire to secure by Letters Patent, is

1. In a printing press, the'combination With a design member having a yielding surface, of an impression member having a rigid ink-repelling impression surface, substantially as described.

In -a printing press, the combination with a design member having a yielding surface, of an impression member comprising a support and a removable and replaceable impression device having a rigid inkrepelling impression surface, substantially as described.

3. In a printing press, the combination with a design member having a yielding surface, of an impression member having a rigid impression surface which when moistened becomes ink-repelling, and means for moistening the impression surface, substantially as described.

4. In a printing press, the combination with a. design member having a yielding surface, and an impression member comprising a supportand a removable and replaceable impression device having a rigid impression surface which when moistened becomes inlcrepelling, and'means for moistening the impression surface, substantiallyv as described.

5. In a rotary printing press, the combi nation with a design cylinder having a yield ing surface, of an impression cylinder having an ink-repelling impression surface, sub stantially as described. I

6. In a rotary printing press, the combination with a design cylinder having a yield ing surface, of an impression cylinder comprising a rotary sufiort and-a removable and replaceable impression device having an ink-repelling surface, substantially as described.

7. In a rotary printing press, the combination with a design cylinder having a yielding surface, of an impression cylinder comprising a rotary support and a removable and replaceable impression device having an. impression surface which when moistened becomes ink-repellingand means for moistening the impression surface, substantially as described.

8. In a rotary printing press, the combination with a primary design member, of a secondary design member having a yielding surface, an impression member having a rigid ink-repelling impression surface, sub

stantially as described.

pression surface which when moistened be comes ink-repelling, and means for moistenmg the impressionsurface, substantially as described.

'10. In a multi-color printing press, the

combination with a plurality of design members for printing on one side of the paper, of a perfecting design member having a yielding surface, and an impression member for the perfecting printing member, the impression member having a rigid ink-repelling impression surfuce, substantially as described.

11. In a rotary multi-color printing press, the combination with a plurality of design cylinders for printing on one side of a Web, of a perfecting design cylinder having a yielding surface, and an impression cylinder for the perfecting printing cylinder, said impression cylinder having an ink-repelling impression surface, substantially as described.

12. In a multi-color printing press, the combination with a plurality of design members for printing on one side of the paper, of a perfecting design member having a yielding surface, an impression member for the perfecting printing member, the impression member having a rigid impression surface which when moistened becomes ink-repelling, and means for moistening the impression surface, substantially as described.

13. In a rotary multi-color printing press, the combination with a plurality of design cylinders for printing on one side of a web, of a perfecting design cylinder having a yielding surface, an impression cylinder for pression cylinder having an impression surface which when moistened becomes inkrepelling, and rollers for applying moisture directly to the impression surface, substantially as described.

14:. A multicolor web printing press including in combination, a circumferentially continuous impression drum, a plurality of circumferentially continuous planographic design cylinders with said impression drum to print one side of the paper, and means for printing a design on the other side of the paper, while the ink applied to the firstside thereof is in a fresh or undried state and without removing any of the ink appliedto the first side, the web being led directly from the first printing mechanism to the second printing mechanism, substantially as described.

arranged to cooperate- 110 the perfecting printing cyllnder, said 1mw 15. A rotary multicolor printing press in-' eluding in combination, an impression drum, a plurality of design cylinders for printing on one side of the paper carried by the drum, and means comprising an impression memher having a circumferentially continuous rigid ink-repelling surface, and a suitable design member for printing on the other side of the paper, While the ink applied to the first side thereof is in a fresh and undried state.

16. A printing press including in combination, a design member having a yielding surface and an impression member having 1 an ink repelling surface.

17. A rotary multicolor printing press including in combination, a plurality of design cylinders for printing on one side of the paper, and means including a design cylinder having a yielding surface and an impression member having an ink repelling surface for printing on the opposite side of the paper.

' In testimony whereof, I have signed my name to this specification, in the presence of 25 two subscribing witnesses.

GEORGE E. PANGOAST.

Witnesses:

JACOB M LLER, GEORGE ScHIEoK. 

